One patient died, six recovered and one remained under medical supervision in the cities of Abbotabad and Mansehra, he said.

Patients were taken to medical facilities after presenting with the flu-like symptoms typical of avian flu. Health officials believe that another person's death was likely caused by bird flu, but has not been confirmed.

Some of the deaths occurred within a single family, raising concern -- but no proof -- that the disease may have spread through human-to-human contact, said officials, who called for further analysis.

"We would be remiss if we didn't investigate further, " said Hartl from the WHO headquarters in Geneva. "Our concern is that once this virus remains in the animal population, it mutates into a more transmissible form. And the more they (the viruses) stay in the animal population, then we have a panic situation."

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Public health officials worry that, should the virus gain the ability to transmit easily among humans, a pandemic could occur. Given that the disease is often fatal, the impact could be catastrophic, they contend.

Hartl praised Pakistan's Ministry of Health for investigating the outbreak in hospitals in remote areas.

Though this marks Pakistan's first outbreak of bird flu among people, several outbreaks of H5N1 influenza have occurred among poultry in Pakistan, and it spread to the country's wild birds earlier this year, the WHO said.

Some cases among birds have been reported in the capital city of Islamabad, but most have been reported in Pakistan's "poultry belt" in the North-West Frontier province.

In another part of Asia, Indonesia's Ministry of Health announced Tuesday the death of a 47-year-old man from Banten Province, who died December 13.

Of the 115 confirmed cases in Indonesia, 93 have been fatal, according to WHO.

Since 2003, the health agency has tallied 341 cases among people in 14 countries, 210 of them fatal. E-mail to a friend